Elena Piskounova

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The differentiation of tumorigenic cancer stem cells into nontumorigenic cancer cells confers heterogeneity to some cancers beyond that explained by clonal evolution or environmental differences. In such cancers, functional differences between tumorigenic and nontumorigenic cells influence response to therapy and prognosis. However, it remains uncertain(More)
Lin28A and Lin28B selectively block the expression of let-7 microRNAs and function as oncogenes in a variety of human cancers. Lin28A recruits a TUTase (Zcchc11/TUT4) to let-7 precursors to block processing by Dicer in the cell cytoplasm. Here we find that unlike Lin28A, Lin28B represses let-7 processing through a Zcchc11-independent mechanism. Lin28B(More)
Lin28 and Lin28B, two developmentally regulated RNA-binding proteins and likely proto-oncogenes, selectively inhibit the maturation of let-7 family microRNAs (miRNAs) in embryonic stem cells and certain cancer cell lines. Moreover, let-7 precursors (pre-let-7) were previously found to be terminally uridylated in a Lin28-dependent fashion. Here we identify(More)
The developmentally regulated RNA-binding protein Lin28 blocks processing of let-7 family microRNAs (miRNAs) in embryonic cells. The molecular basis for this selective miRNA processing block is unknown. Here we find that Lin28 selectively binds the terminal loop region of let-7 precursors in vitro and that the loop mediates miRNA processing inhibition in(More)
Solid cancer cells commonly enter the blood and disseminate systemically, but are highly inefficient at forming distant metastases for poorly understood reasons. Here we studied human melanomas that differed in their metastasis histories in patients and in their capacity to metastasize in NOD-SCID-Il2rg(-/-) (NSG) mice. We show that melanomas had high(More)
The pluripotency factor Lin28 recruits a 3' terminal uridylyl transferase (TUTase) to selectively block let-7 microRNA biogenesis in undifferentiated cells. Zcchc11 (TUTase4/TUT4) was previously identified as an enzyme responsible for Lin28-mediated pre-let-7 uridylation and control of let-7 expression. Here we investigate the protein and RNA determinants(More)
Studies of human cancer metastasis have been limited by a lack of experimental assays in which cancer cells from patients metastasize in vivo in a way that correlates with clinical outcome. This makes it impossible to study intrinsic differences in the metastatic properties of cancers from different patients. We recently developed an assay in which human(More)
AIM To investigate LIN28B gene variants in children with idiopathic central precocious puberty (CPP). PATIENTS AND METHODS We studied 178 Brazilian children with CPP (171 girls, 16.8% familial cases). A large multiethnic group (1,599 subjects; Multiethnic Cohort, MEC) was used as control. DNA analysis and biochemical in vitro studies were performed. (More)
legends and data plotted as –ΔΔCt. Left and right panels depict the results for Lin28 and Zcchc11, respectively. For each panel, the upper right quadrant contains those miRNAs that are reproducibly upregulated by both siRNA knockdown sets. Depicted errors bars are ±s.e.m. (b) Luciferase reporter assays to evaluate the in vivo relevance of elevated mature(More)
Reactive oxygen species (ROS) are highly reactive molecules that arise from a number of cellular sources, including oxidative metabolism in mitochondria. At low levels they can be advantageous to cells, activating signaling pathways that promote proliferation or survival. At higher levels, ROS can damage or kill cells by oxidizing proteins, lipids, and(More)